1. Technical Field
The present technical field relates to electric storage devices typically used for regeneration or power storage in a range of electronic devices and hybrid vehicles, and manufacturing methods thereof.
2. Background Art
FIG. 21 is a front sectional view of an electric double-layer capacitor, which is an example of a conventional electric storage device. This capacitor includes capacitor element 101, two collector plates 102, tubular metal case 105 with bottom 105A, terminal plate 103 partially exposed to the outside of case 105, and sealing rubber 106.
Capacitor element 101 includes positive electrode end 101A and negative electrode end 101B (hereafter referred to as ends 101A and 101B) at opposed positions. Collector plates 102 are welded to ends 101A and 101B, respectively. Capacitor element 101 is housed in case 105 such that collector plate 102 welded to end 101B faces bottom 105A. Collector plate 102 welded to end 101A is disposed at an opening of case 105, and is coupled to terminal plate 103. Sealing rubber 106 is provided between terminal plate 103 and the opening of case 105 to insulate them. Horizontally drawn part 105B is formed from the outside to inside of the opening of case 105 against sealing rubber 106 so that sealing rubber 106 is compressed to seal the opening. In addition, an end of the opening of case 105 is bent inward to form bent part 105C.
Capacitor element 101 includes a positive electrode, a negative electrode, and a separator (none of them are illustrated). Each of the positive electrode and the negative electrode is configured by applying an electrode layer containing carbon material to a strip of collector except for one end. In capacitor element 101, these positive and negative electrodes face each other and are shifted such that portions without electrode layers on their collectors protrude in the opposite directions, and are wound with the separator therebetween. Accordingly, the portions without electrode layers of the electrodes configure ends 101A and 101B, respectively.
Terminal plate 103 is provided with a through hole for linking inside and outside case 105. Pressure-adjusting valve 104 for preventing pressure rise inside case 105 is provided so as to cover this through hole in.
In this structure, sheet-like electrodes and collectors 102 are in plane contact, respectively, to take out current from capacitor element 101. Accordingly, power can be collected at low resistance inside electric double-layer capacitor (e.g., Japanese Patent Unexamined Publication No. 2009-194131).